I have been to lots of games at RES, some of them BYU, some of them MWC, and several PAC-12 games. The experience depends on whether you can be good natured about some of the utterances that will surely be coming your way from Utah fans. Some people will be fine with you; others will not. Some of the ribbing will be in good fun; some of it will come from the depths of the disdain they have for all things BYU. Sometimes you sit next to fun and interesting people. Other times, you sit next to people who have had a bit too much to drink and run their mouths the whole time. The heterogeneity of their fan base (middle-class members from Davis County mixed in with working-class agnostics from West Valley, secular hipsters from Salt Lake City with students from the Institute) creates an interesting vibe. My experiences there have been inconsistent--great one game, horrible the next.